The SENT protocol (SAE J2716 standard) provides signal transmission from a transmitter device, e.g. an integrated circuit (IC) sensor, to a receiver device, e.g. an Electronic Control Unit (ECU). The SENT protocol may for example provide a low-cost and efficient alternative to, for example, analogue or PWM interfaces for sensor applications.
The SENT encoding scheme may be particularly suitable for use in applications where high resolution sensor data needs to be communicated from a sensor to an ECU. The SENT standard defines a unidirectional communications scheme from a transmitting device, e.g. a sensor, to a receiving device, e.g. a controller, which does not require a coordination and/or synchronization signal from the receiving device. Thus, the transmission may proceed independently of the receiver module.
An integrated circuit sensor for automotive applications may provide an output mode for reporting sensor information and/or other diagnostic information, such as cyclic redundancy check (CRC) information, via a SENT telegram compliant with the SAE-J2716 Surface Vehicle Information Report standard. The number of nibbles is typically fixed for each application of the encoding scheme, but can vary between applications.
An integrated circuit (IC) device for SENT communication as known in the art may use a fixed configuration for its communication channels, e.g. defining a data mapping to fast and slow channels. Thus a device, e.g. a transmitter or receiver device as known in the art, that is adapted for SENT communication may have a configuration-specific hardware design or firmware to take the SENT protocol configuration into account.
The SENT serial data communication protocol may be used for transmission of signal values, e.g. messages, from a transmitter device to a receiver device with high resolution. The implementation of the SENT protocol in IC implies a fixed user message configuration for its communication channels, e.g. fast and slow channels. The configuration may depend on the intended application, and changing the configuration in order to address different applications may require redesign of the IC hardware and/or firmware.
For example, the configuration may be hardwired, such that the IC device is specifically designed for a single configuration corresponding to a specific application. Alternatively, the IC device may be provided by a read-only memory (ROM) which can be programmed for a specific SENT message configuration. Thus, the IC can be redesigned for a different configuration by adapting the firmware accordingly; however, the end-product device provided with such application-specific ROM may be only suitable for use in the configuration the firmware is designed for.
The device may comprise a one-time programmable non-volatile memory (OTP), such that the change of the SENT message configuration can be realized through programming the device with a suitable software construct, taking into account the restrictions of the available memory space. Thus, a device can be programmed to a specific application after manufacturing but prior to use. Furthermore, an IC device may also comprise a FLASH memory or an electrically erasable programmable read-only memory (EEPROM), such that the change of the SENT message configuration can be realized through software change, taking into account restrictions of the available memory space.
Configuration of an integrated circuit SENT transmitter device may comprise, for the SENT fast channels, e.g. the data transmitted via the data nibbles, defining the number of channels, the information associated with each channel, the data nibbles order format, the method of status bits processing, the fast channel diagnostic error codes and the reporting priority of the fast channel diagnostic error codes. Furthermore, configuration for the SENT slow channels may further comprise the defining of the association of every SENT slow channel message with an ID number, an ID memory location, a message order, the slow channel diagnostic error codes and the reporting priority of slow channel diagnostic error codes.